Stuck seat posts & frame heating discussion

For discussions about bikes and equipment.
User avatar
Si
Moderator
Posts: 14961
Joined: 5 Jan 2007, 7:37pm

Stuck seat posts & frame heating discussion

Postby Si » 19 Sep 2008, 8:28am

fatboy wrote:I decided yesterday that it was time to take my seatpost out and re-grease etc. Well I can't! It's an ITM alloy post (painted black) in a 520 steel frame. The seatpost is the right size just obviously not greased enough.

I've taken the bolt all the way out. I've put a screwdriver between the lips and eased them apart a bit. I've loaded it with WD40 and finally I took the saddle off and put the top of the post in a workmate and tried turning the frame. All I did was damage the MDF on the workmate.

Any ideas? I'm not in a great hurry to get this done and I'm loathed to go down the route of sawing the seatpost out. Will repeated applications of WD40 over time help? Also could cooling the post down using a plumbing freezer colar help?


cambsos wrote:For a start you need a better penetrating liquid such as Plusgas, use liberally over a few days from the bottom bracket and around the seat tube/seatpost junction.

If that doesn't work using the method you have already tried you may have to cut it out in by using a hacksaw blade. Saw it off leaving about an inch or so protruding Cut it into segments very carefully so as not to damage the frame and you should be able to peel it out with pliers.


markis42 wrote:If you are not bothered about the post find a suitable steel to put inside the current seat post to stop it crushing then clamp on the outside with mole grips.Liberal applications of plusgas and the a waggle from side to side until it breaks loose.It may take a little time but i think its easier then sawing and the only thing to damage is the post and er possibly your back.
Good luck.


fatboy wrote:Rather than taking the BB out, can I squirt it in through the bottle cage braze ons? Then I can keep riding the bike.


Mick F wrote:I don't see why not, it just would be easier via the BB to make sure it get in properly. The seat tube would be more in line with the offending seat pin.

Actually, if your seat pin is stuck, how's your BB? Maybe it would be a good idea to check.


Mick F wrote:I don't see why not, it just would be easier via the BB to make sure it get in properly. The seat tube would be more in line with the offending seat pin.

Actually, if your seat pin is stuck, how's your BB? Maybe it would be a good idea to check.


steady eddy wrote:Warm the frame cool the seat post - the different coefficients of expansion between the aluminium and the steel should assist in solving the problem.
A hair dryer on the frame should provide sufficient heat but keep the paint intact some ice from the fridge crushed up into the seat tube should do the cooling bit but get everything dry and clean before it all goes back together.
To get better torque on the seat tube, assuming that you are going to bin it, drill right through it and put a bar or a big screwdriver in to give you more leverage in trying to turn it.


CJ wrote:
fatboy wrote:Rather than taking the BB out, can I squirt it in through the bottle cage braze ons? Then I can keep riding the bike.

Not much point if you're going to keep on riding the bike, since the Plus-Gas will drain away from where its wanted and spend all day trying to dissolve the rust in your bottom-bracket!

If still riding it you might simply ride without the bolt and put a few drops around the top of the seat tube every time you get the bike out.

I'm afraid your experience proves that "greasing" the seatpost isn't really the best thing to do. Time to get some anti-seize compound I think! Remember to take it with you, and the bolt, when out on a Plus-Gas ride, as there's no predicting when it'll start to loosen - if ever!


hubgearfreak wrote:
steady eddy wrote:To get better torque on the seat tube, assuming that you are going to bin it, drill right through it and put a bar or a big screwdriver in to give you more leverage in trying to turn it.


the saddle is a good lever. :D

and despite what everyone says about plusgas, sheldon wrote
Aluminum seatposts frequently become stuck by corrosion also, and penetrating oil is almost useless against aluminum oxide. Fortunately, aluminum oxide can be dissolved like magic by using ammonia.



have you tried ammonia?

of course he also wrote an article on the subject
http://sheldonbrown.com/stuck-seatposts.html


cambsos wrote:Maybe that was alu post in an alu frame?

It certainly worked in an old DBR steel frame with a alu seatpost.


richardirving wrote:I had a stuck seatpost in a tandem earlier this year. It had been stored for about 7 years and I really thought I had a nightmare job on my hands. I followed Tony Oliver's advice in 'Touring Bicycle.' Cool the frame and seatpost using freezer blocks (held on with old toe straps) wrapped around with insulation (old blanket works well enough) for a few hours. Then apply heat to the frame immediately around the seatpost by using a thick tea towel soaked in boiling water. Immediately try to remove the seatpost as you only have limited time before the seatpost expands - and seizes again. It definitely works and I saved the seatpost - remembering to grease it well before reinserting it!


fatboy wrote:It's out :lol:

After one week of WD40 with no movement. Two hours of Plus-Gas did the trick. Seat post fine, saddle fine, Fatboy happy!

This evening when I get home the post is coming out and it going to be smothered with grease, I will also get myself some anti-sieze stuff and take my seat post out bi-annually.

Thanks for all your, as usual, invaluable advice


------------------------------

7_lives_left wrote:I remember reading this on the Sheldon Brown site
http://sheldonbrown.com/stuck-seatposts.html

I think you need different approaches depending on whether the seat post is steel or alloy (and the frame for that matter).

If you are using WD40 or Plusgas you have to be patient and keep applying over a long period of time. It will probably help if you are still riding the bike rather than leaving it in the garage. Leave the clamping bolt loose.

Also, the proprietor of my local bike shop told me that if you are really desperate, after WD40 or plusgas has failed, try Coca cola. It contains phosphoric acid which corrodes metal and rust, freeing the parts. I'm not recommending this, just reporting what he told me!


Asdace wrote:I was to mention that, but gentle heat of the torch, waving it side to side should budge it. But is it jammed or corrodised.


PW wrote:The Coca Cola trick is popular with the Americans, they also use something called Root Beer. Another one is ammonia if you can find a source for it.
Once it's had the treatment put the post in a bench vice and use the frame as a lever to get it moving.
If all else fails saw it off flush with the top of the seat tube, then use a hacksaw blade with a rag wrapped around it to cut the post into segments, like an orange -but be careful not to wreck the frame! Then peel the segments out with an old chisel or unwanted screwdriver.



john4703 wrote:If it is well stuck and damaging it does not matter try removing the saddle then tapping the end of the post with a hammer after applying lots of freeing oil. This should break any corrosion and make it possible to remove it. Be careful not to send it right down inside the frame.


pioneer wrote:Here's another one. (But only if you don't want to use the same seat-post again).
A liberal dribbling of Plus Gas and leave over night.
Next day.
A bit of gentle warming helps,i.e. leave in the sun for a couple of hours if possible.
Then drill through the seat-post just above the seat clamp.
Shove through a bar (a suitably meaty' screwdriver will suffice) and use it as lever to twist the post to and fro. When (if) loosened, gently twist the seat-post up and out.

It takes patience and time but it will work.


Mick F wrote:It all sounds good to me.

Try a vice too, using the frame as leverage. It'll wreck the seatpost, though!
The thing is, if it's stuck and you want it out, it's obvious that the post is for the scrap heap anyway.

Conversely, if it's stuck, and you actually want it in the position it's in, just wanting to remove it to clean/maintain - leave it where it is!

Horse - barn door - closing - after - bolting. Rearrange those words a bit. Grease would've helped in the first place. (sorry for saying that!)


jezer wrote:Years ago I bought a second hand bike from a clubmate. He was shorter than me so I needed to raise the saddle, but he was obviously not into regular maintenance because the seat pin was well and truly stuck. I tried WD40 and similar but nothing worked. LBS tried and managed to snap the pin off close to top of seat tube leaving the stump still stuck inside.

I 'phoned a well known frame builder who said it was no problem, they would "melt it out". They had to respray the frame afterwards, and it looked like new. I rebuilt the bike and it lasted me another 10 years.

Ever since then I remove the seatpin and smear a small amount of grease on it about twice a year.



7_lives_left wrote:
PW wrote:The Coca Cola trick is popular with the Americans ... Another one is ammonia if you can find a source for it.

I ought to point out that the phosphoric acid in Coke attacks iron and steel (don't know about stainless variety), but leaves aluminium alone I think. They deliver Coke in aluminium cans after all.

Ammonia on the other hand attacks aluminium and largely leaves iron and steel untouched. It also evaporates leaving very little trace, which is important because 'salts', like road salt or the residue from Coke can form batteries that promote galvanic corrosion.

I wouldn't want to use ammonia on an aluminium frame bike and I wouldn't want to use Coke on a steel frame bike.

You used to be able to buy household ammonia as a cleaning product. Maybe you can't nowadays. All the interesting chemicals seem to disappear from the shelves because of health and safety.


----------------------------

Lawrie9 wrote:If you have a light weight steel frame it is worth knowing that an alloy seat post can sort of weld itself or fuse to the frame making it almost impossible to move. I'm not a scientist but there is a chemical reaction between alluminium and steel that causes them to fuse together. For more info check the lightweight classics website. I would probably remove the post quite frequently and rub it with fine wire wool and clean with white spirit and clean any corrosion from inside the frame.


Simon Cole wrote:You just need to attach a more reactive metal to the steel so that it reacts instead. Try a zinc pencil sharpener.


piedwagtail91 wrote:i've been using grease and more recently copper slip inside the seat tube for the last 30 odd years and this seems to have prevented the problem.


Diogenes wrote:It is a straightforward corrosion issue associated with the dissimilar metals. Easiest solution is to smear the seat post with an antisieze compound such as coppaslip. You can use grease but an antisieze is designed to do just that.

Getting stuck posts out is a real challenge so prevention is better than cure. Pull the post out every few months and apply fresh antisieze, I do mine every 6 months or so.

D :D



JohnW wrote:A nasty problem and a common one.

I can't add to the above advice, but if it's happened to you before, have you learned the lesson of history?

For the future, as you are assembling the bike and before you insert the seat-pin, try liberally coating the seatpin and as far down the seat tube as you can get with Millers Black-Moly D180. Don't leave any bare metal for steel to alloy contact. Any grease will help of course, but this is one that our local fire brigade use on threads in their pumps : it's formulated for under water use. It works!

If your seatpin is fluted and the flutes extend below the top of the seat tube, make sure they're well filled with the grease.

If you buy ready-built bikes, this is one of the matters to address before you ride it.

JohnW



meic wrote:How about knocking it IN a bit. This may help to break the bond. You will be able to give it a hefty blow from above with a hammer and you had already decided to destroy the seat post so you havent much to lose.
Then retry all the other methods to see if it has helped.


CJ wrote:The final solution - in both senses literally - is cuastic soda, administered to the inverted frame via its bottom bracket. It will dissolve the aluminium seatpost but leave the steel frame unharmed. It will also dissolve skin, floorboards, concrete ... so don't forget to put a plastic bucket underneath to catch the remains.

Caustic soda is sold for cleaning drains.

br8ker
Posts: 23
Joined: 11 Jan 2013, 6:50pm

frame strength after melting out stuck seatpost

Postby br8ker » 20 Jun 2013, 4:38pm

hi

ive got 90s marin frame that i want to use for a year cycle tour but it has one problem - stuck seatpost.
It's an aluminium seatpost in a steel frame. I spoke with a bike shop & they said that they could apply high heat to the steel and then just pull the aluminium seatpost out...
they say that the frame will be structurally sound after this,.. but was wondering what people think? should i worry about welds that are in that area? will they be weakened by this kind of heat application?

User avatar
gaz
Posts: 13355
Joined: 9 Mar 2007, 12:09pm
Location: Kent, car park of England

Re: frame strength after melting out stuck seatpost

Postby gaz » 20 Jun 2013, 5:27pm

Hand wash only. Do not iron.

User avatar
Greybeard
Posts: 1332
Joined: 1 Oct 2008, 6:48pm
Location: East Yorkshire

Re: frame strength after melting out stuck seatpost

Postby Greybeard » 20 Jun 2013, 6:01pm

Been there, done that - got the holes in the T-shirt :shock:

viewtopic.php?f=5&t=44582&p=361017&hilit=caustic+soda#p361017

Steve

User avatar
cycleruk
Posts: 5054
Joined: 17 Jan 2009, 9:30pm
Location: Lancashire

Re: frame strength after melting out stuck seatpost

Postby cycleruk » 20 Jun 2013, 8:25pm

br8ker wrote:hi
"should i worry about welds that are in that area? will they be weakened by this kind of heat application?


Welds? More like brazing which may melt if heated up too much.
I don't know the temperature difference between melted ali' and brazing. :roll:
I wouldn't have thought the paint would like that either.
There's no such thing as a tailwind.
It's either a headwind, or you're going well.

rualexander
Posts: 2300
Joined: 2 Jul 2007, 9:47pm
Contact:

Re: frame strength after melting out stuck seatpost

Postby rualexander » 20 Jun 2013, 8:26pm

br8ker wrote:hi

ive got 90s marin frame that i want to use for a year cycle tour but it has one problem - stuck seatpost.
It's an aluminium seatpost in a steel frame. I spoke with a bike shop & they said that they could apply high heat to the steel and then just pull the aluminium seatpost out...
they say that the frame will be structurally sound after this,.. but was wondering what people think? should i worry about welds that are in that area? will they be weakened by this kind of heat application?

I had this done a few years ago to a Specialized Rockhopper steel frame, no problem apart from the paint being burnt off within about four or five inches of the seatpost, so needed repainting in that area.

rualexander
Posts: 2300
Joined: 2 Jul 2007, 9:47pm
Contact:

Re: frame strength after melting out stuck seatpost

Postby rualexander » 20 Jun 2013, 8:28pm

cycleruk wrote:
br8ker wrote:hi
"should i worry about welds that are in that area? will they be weakened by this kind of heat application?


Welds? More like brazing which may melt if heated up too much.
I don't know the temperature difference between melted ali' and brazing. :roll:
I wouldn't have thought the paint would like that either.


90's Marin is probably welded

Slidingpillar
Posts: 119
Joined: 4 Sep 2009, 1:46pm

Re: frame strength after melting out stuck seatpost

Postby Slidingpillar » 20 Jun 2013, 8:53pm

Have you exhausted all the options in Sheldon Brown's page?

I'd be trying very hard, although the thing that often gets stuck things working is time! I freed a stuck vintage car's speedo by pickling it in paraffin, but it was a month before anything started to move. But for something that hadn't moved for at least 40 years, I didn't think that was bad.
Trice Q
Longstaff Trike

Brucey
Posts: 32774
Joined: 4 Jan 2012, 6:25pm

Re: frame strength after melting out stuck seatpost

Postby Brucey » 20 Jun 2013, 9:12pm

you will alter the temper of the steel by heating it up like that. It could go soft, lose toughness... or even both.

There are many cold techniques for shifting seat posts that don't leave you with a potentially weakened frame that needs a respray, so I'd look to use those, tbh.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

User avatar
531colin
Posts: 12324
Joined: 4 Dec 2009, 6:56pm
Location: North Yorkshire

Re: frame strength after melting out stuck seatpost

Postby 531colin » 20 Jun 2013, 10:51pm

aluminium posts corrode in steel frames, its the oxide (or whatever) that's filling the gap between post and frame
try these, in this order.......
1) take the saddle off, give the seatpost a sharp crack with a one pound hammer....if it moves down, it will twist....if it twists.....etc
2) warm the seat tube up with a hair dryer....for long enough and hot enough to dry out all the oxide.....maybe an hour?....when dry, it takes up less space....while you do that, put some Plus Gas or light oil round the top of the post, its better to have oil in there than wet oxide.....give it one more crack.
3) Hmmmm. it really is stuck. OK, household Ammonia (from your chemist) will dissolve that pesky oxide, given time. Put the bike upside down, get Ammonia into the seat tube via the bottle boss or the bottom bracket, and wait. Give it a week, replacing the Ammonia solution daily, or thereabouts.
4) last resort time.....think about cutting it out with a hacksaw, or drilling/reaming it out or dissolving it in caustic soda.....then go through the above one more time.....cutting/reaming etc. is the pits!

If anybody agrees, can we have this in Too Good To Lose?.....I didn't find the current entry very useful.

landsurfer
Posts: 4331
Joined: 27 Oct 2012, 9:13pm
Location: Rotherham

Re: Stuck seat posts & frame heating discussion

Postby landsurfer » 20 Jun 2013, 11:16pm

If your seat post is stuck in a steel frame send it, or drop it off to me.
I'll remove it without any damage to the frame tube.
Removed 14 so far using a well practiced cutting system.
The good old "skin knife" process, as used for skin repairs on alloy airframes.
£20 / frame ....

Sorry, this is not a ' while you wait service', normal turnround 4 days. Because it hurts my hands ....
RSF.
Audax UK.
What if there were no more hypothetical questions?

The road goes on forever.

br8ker
Posts: 23
Joined: 11 Jan 2013, 6:50pm

Re: Stuck seat posts & frame heating discussion

Postby br8ker » 21 Jun 2013, 1:01pm

thanks for all the replies guys!
yeah i've tried so far
* ice+boiling water method to try and shrink the seatpost, then expand the frame quickly
* ammonia (3 days)
* wacking nose of seatpost with a hammer
* pathetic wrenching and turning of the seatpost

i've considered the caustic soda method but think i'll end up injuring myself or someone else.
considered the cutting method but dont trust myself not to cut up the frame....
thanks for the offer landsurfer but given im touring im a bit too paranoid to let someone else cut it either...

@531colin - when you say "replace the ammonia solution daily" do you mean replace it with a fresh new bottle bought from the shop? sounds a bit expensive

thanks for opinions on heat issues...
might give the hair dryer trick a try and if that doesnt work, i'll just buy a new frame.....

User avatar
531colin
Posts: 12324
Joined: 4 Dec 2009, 6:56pm
Location: North Yorkshire

Re: Stuck seat posts & frame heating discussion

Postby 531colin » 21 Jun 2013, 1:16pm

I assume you are just pouring "some" ammonia into the tube, rather than the whole bottle at once? (but then again, I don't know how big the bottle is.... :? )
So all I'm suggesting is the ammonia is "used" by the process(?) and wants refreshing?

FixedGuru
Posts: 8
Joined: 25 Jun 2013, 4:07pm

Re: Stuck seat posts & frame heating discussion

Postby FixedGuru » 25 Jun 2013, 8:13pm

Prolonged soaking will help, riding around on it won't.

You can cool the seat post from the inside by spraying it with a 'freezing spray' from a plumbers merchant. Heat the tube up with a HAIR DRYER on low, which will probably be around 120 degrees C or so close to the elements, this won't damage the paint layer, but it might wrinkle any transfers/stickers. You may get away with the hot setting on some hair dryers. Then try to get the ammonia/PlusGas/whatever into the gap before physical removal.

Clamp the seatpin into a sturdy bench vice on a heavy bench, with the frame upside down and use the leverage on the frame to try to shift the frame from the pin. If you still cannot shift the pin in the frame you will have to cut it out, you risk damaging the frame itself if you try too hard.

If it shifts but remains too stiff to pull out, you can get (possibly hire) internal bearing pullers which will clamp up inside the seatpin, then have a slide hammer which fits into them to try to extract the seatpin.

If you need to cut the seatpin out, it is best to set it up on a lathe or milling machine and drill, then bore the pin out from the tube. An adjustable reamer may be used to clear out the last of the pin rather than risking machining through the side of the tube. It helps to look up the tube ID and OD first and identify the seatpin diameter.

Otherwise, melt it out with an oxy-acetylene torch and treat yourself to a respray.

Robbied196
Posts: 102
Joined: 25 Apr 2012, 9:03am
Location: Shrewsbury

Re: Stuck seat posts & frame heating discussion

Postby Robbied196 » 27 Sep 2013, 9:27am

I didn't realise there was a dedicated stuck seat posts 'post'.

I have to say some of the above did give me a wry smile. I've removed 'a lot' of stuck seat posts and cutting them out is by far the quickest and easiest option.

It never fails and never damages the paint or frame.

viewtopic.php?f=5&t=63229